[TowerTalk] Square Hole or Round Hole for Self Supporter?

[jimlux]

On 1/22/18 12:06 PM, Richard Thorne wrote:
> Clay,
> 
> I emailed a fella by the name of Jeremy.  He quoted me $2800 for a 10' 
> hole.
> 
>  From the other post's on the subject probably a reasonable number. I'll 
> still research the back hoe method.  I'll bet will be less expensive to 
> use a back hoe and have the dirt hauled off (if needed).
> 


generally that's the case.  Round piers are handy if you're already 
drilling them for some other reason, or if you have limited room on top 
(a 20 foot deep 3-4 ft pier will fit a lot of places)

There's also other schemes - shallower and larger in plan, for instance.

There have been discussions on this list a few years ago about a sort of 
X plan -essentially radial reinforced concrete beams - you could be 
pretty shallow, at the cost of having 10 or 15 foot "arms" sticking out. 
  There are lots of engineering alternatives - there's nothing "special" 
about the "cube" as a base.


Or, if your self supporter isn't a "flagpole" and skinny - Tapered 
towers: HV transmission towers, Windmills and Rohn BX have a lot of 
taper.  I suspect that you don't need a lot of "foundation" under the 
feet for that - enough to keep the downwind leg from sinking, and the 
upwind leg from lifting.